A "revolutionary" savings account that pays all your interest upfront – at a rate of £1,000 for every £12,000 you stash away – has been launched by Spanish-owned bank Santander.

The account is a fixed-rate savings bond where customers have to tie up their money for three years. But while savers taking out such accounts usually have their interest paid in monthly or annual instalments, this product pays all interest, at an effective rate of 3.36%, within the first few weeks.

If a customer opens an account before 20 November with a deposit of £12,000 they will receive £1,000 net interest on 2 December – money they can spend immediately on Christmas presents or a holiday, or reinvest to earn more interest.

Santander claims it is "turning the savings market on its head" with the Upfront Interest Bond. It is aimed at those who have a minimum of £10,000 that they can comfortably afford to lock away for three years. And there is another catch: you need to have, or to open, a Santander current account, as this is where the interest will be paid.

Some will see this as a clever move designed to increase Santander's current account customer numbers – it has made no bones about its determination to boost its 9% share of the market.

Santander offers five current accounts, only one of which doesn't require the customer to pay in a minimum of £1,000 a month. However, several of its current accounts offer people the chance to earn 5% on credit balances for 12 months, so a customer could sign up for the new savings account and then immediately put their upfront interest payment to work in an account paying 5%.

The bank is promoting the savings bond with a TV campaign featuring its new "brand ambassador" US Open champion Rory McIlroy.

Kevin Mountford from price comparison site Moneysupermarket said: "At a time when we face increased expenditure with Christmas and winter fuel bills, this is an innovative way in which you can make use of your savings without having to eat into your capital."

He added: "No doubt higher rates can be earned from other accounts, but the attraction of taking interest now will appeal to many."

The account matures in December 2014, and no further interest will be earned during the term. Potential customers need to be sure they won't need the money they put into the account before it matures as additional deposits, withdrawals or the closure of the account are not allowed during the fixed-term period.